Divided total US commercial petroleum NOx emissions (kt) by total US commercial petroleum fuel consumption (TBtu). Converted from units (kt NOx/TBtu) to units (kg NOx/MMBtu). Multiplied by LPG propoane heating value to convert to units (kg NOx/gal). Heating values for liquid fuels were changed from MMBtu / Barrel to MMBtu / gallon using 42 gallons / barrel. All factors are Higher Heating Values, as used by the US EPA. LPG heating value based on total consumption data.

Divided total US commercial coal NOx emissions (kt) by total US commercial coal fuel consumption (TBtu). Converted from units (kt NOx/TBtu) to units (kg NOx/MMBtu). Multiplied by coal heating value to convert to units (kg NOx/short ton). Heating values for liquid fuels were changed from MMBtu / Barrel to MMBtu / gallon using 42 gallons / barrel. All factors are Higher Heating Values, as used by the US EPA. The heating value for coal is "Commercial Coal."

NOx emissions for commercial wood combustion were not available, so NOx emissions for residential wood combustion were used instead. Residentail wood was selected from the GHG Inventory after comparing the range of calculated emissions factors to those in the EPA AP-42 database for commonly used wood boilers in commercial combustion (e.g., fluidized bed, stoker boilers). Divided total US residential NOx emissions (kt) by total US residential wood fuel consumption (TBtu). Converted from units (kt NOx/TBtu) to units (kg NOx/MMBtu). Multiplied by wood heating value (for wood & waste) to convert to units (kg NOx/short ton). All factors are Higher Heating Values, as used by the US EPA.

Divided total US commercial petroleum NOx emissions (kt) by total US commercial petroleum fuel consumption (TBtu). Converted from units (kt NOx/TBtu) to units (kg NOx/MMBtu). Multiplied by residual oil heating value to convert to units (kg NOx/gal). Heating values for liquid fuels were changed from MMBtu / Barrel to MMBtu / gallon using 42 gallons / barrel. All factors are Higher Heating Values, as used by the US EPA. Residual bioheat heating value is a weighted average between residual oil (80%) and B100 (20%).

Divided total US commercial petroleum NOx emissions (kt) by total US commercial petroleum fuel consumption (TBtu). Converted from units (kt NOx/TBtu) to units (kg NOx/MMBtu). Multiplied by distillate oil heating value to convert to units (kg NOx/gal). Heating values for liquid fuels were changed from MMBtu / Barrel to MMBtu / gallon using 42 gallons / barrel. All factors are Higher Heating Values, as used by the US EPA. Distillate bioheat heating value is a weighted average between distillate oil (80%) and B100 (20%).